Dyeing leather



Patented Dec. 24, 1935 UNITED STATES PATENT OFFICE DYEING LEATHER.

No Drawing. Application November 22, 1934,

Serial No. 754,870. In Germany December 3, 1

4 Claims.

This invention is an improvement in or modification of that described inthe specification of a patent application Ser. No. 754,369 filed by thesame inventor on the same day. That specifica- 5 tion relates to theapplication of a certain group of amino-azobenzene-dyestuifs for dyeingleather, especially chrome leather, throughout.

According to the present invention, leather, especially chrome leather,can be through-dyed to a substantial degree or even completely by usinginstead of the dyestuffs used in the aforesaid specificationamino-azobenzene sulphonic acids containing in the residue of thecoupling component an amino-group substituted by a monoor poly- 15hydroxyalkyl group. Hitherto N-hydroxyalkylated acid azo-dyestuifs havebeen used only for dyeing textile fibres.

The yellow azo-dyestufis hitherto used for dyeing leather, such asOrange II from diazotized sulphanilic acid and B-naphthol (SchultzFarbstofftabellen, 6th edition, No. 139) or Metanil Yellow Extra fromdiazotized metanilic acid and diphenylamine (Schultz, No. 134) orthenitrated azo-dyestufi from diazo-sulphanilic acid and diphenylamine(Schultz, No. 141) are capable of dyeing chrome leather onlysuperficially. In contrast thereto the dyestuffs used in accordance withthe invention penetrate deeply into the leather and in most cases theydye it completely through. Leather, especially chrome leather, which hasbeen dyed in accordance with the invention has great advantages. Itssection is dyed throughout so that undyed portions are not exposed bydamage to the surface or by wear during use.

Only a few dyestuffs which are capable of penetrating deeply into theinterior of the hide or of dyeing chrome leather throughout havehitherto been known; for example, the yellow mono-azodyestuffs which areobtained from diazotized 2- chloro-4-amino l methylbenzene 6 sulphonicacid and resorcinal or a substitution product or homologue thereof dyechrome leather completely through. By the provision of a whole series ofdyestuffs which are capable of penetrating into the interior of theleather without the addition of alkali and of dyeing it through to asubstantial Dyeing prescription 55 The neutralized hides are dyed in thecask with 150-200 per cent of water at a temperature of 65 C. The caskis set in motion and a solution of the dyestuff is introduced throughthe hollow axle of the cask. After 45 minutes the fat liquor is addedand the cask isthen kept in motion for a further 45 minutes. In the caseof particularly heavy hides the duration of the dyeing must be suitablyprolonged. In general a quantity of dyestuff amounting to 1-2 per centof the weight of the material sufiices for producing powerfulthrough-dyeings.

The dyestuffs used in accordance with the invention may be made by theusual method, which is illustrated in the following examples. In theseexamples and in the table are described the production, composition anddyeing properties of a number of representatives of the group ofdyestuffs of the amino-azobenzene series, but it will be understood thatthis does not exhaust all the possibilities within the scope of theinvention.

In the following examples the parts are by weight:-

Example 1 173 parts of 3-aminobenzene-1-sulphonic acid are diazotized inthe usual manner and the diazosolution is combined at 0-3 C. with 181parts of dihydroxy-ethyl-aminobenzene which has previously beendissolvedby means of the quantity of hydrochloric acid required to produce asolution which is faintly acid to Congo. The reaction is maintained'faintly acid to Congo by addition of a solution of sodium acetate. Whenthe formation of the dyestufi is finished the solution is made weaklyalkaline by the addition of sodium carbonate, heated and the dyestuffprecipitated by salting out. The dyestuff is a yellow crystalline powderwhich dyes leather, especially chrome leather, according to theforegoing prescription a powerful yellow throughout. The dyestufi ofthis example has the following formula:

' (EH40 H S 03 Example 2 127.5 parts of Z-chloro-l-aminobenzene arediazotized in the usual manner and the diazocompound is coupled in amedium acid with acetic acid with 261 parts of3-dihydroxy-ethylaminobenzene-l-sulphonic acid. When coupling isfinished the dyestufi is isolated by salting out after the solution hasbeen made alkaline with sodium carbonate. The dyestufi is a yellowpowder which dyes chrome leather a powerful yellow both on the surfaceand in the interior. The dyestufl of this example has the followingformula:

0 1 so. Gin H Example 3 CgHgOH The dyestufl of mula Example 4 218 partsof 5-nitro-2-aminobenzene-l-sulphonic acid are diazotized with therequired quantity of nitrite and hydrochloric acid and thediazo-compound is coupled with 215.5 parts of3-chloro-1-dihydroxyethylamincbenzene in a solution which is faintlyacid to Congo. addition of sodium acetate the reaction is maintainedfaintly acid to Congo throughout the coupling. When the formation of thedyestufi" is finished the solution is rendered alkaline by the additionof sodium carbonate and the dyestufl is isolated in the usual manner. Itis obtained in the form of a dark red powder which dyes chrome leatherdeep Bordeaux red shades on the surface and dark red-violet shades inthe interior. The dystuff of this example has the following for- By theTable Dyestufl. Dyeing on leather Diem-component ,Azo-component 0n thesurface In the interior 2 chloro- 1 aminobenzene 3 dioxyethylaminobenzene 1 sulphonic P werful yellow. Powerful yellow, 2:5 dichloro 1aminobenzene; 3 P dio xyethylemino benzene l sulphonic Deep orange Deeporange.

3:4 dlchloro l eminobenzene..

Z-nitro-l-eminobenzene 3-nitro-l-aminobenzene 4-nitro-l-eminobenzen4-nitro-l-aminobenzene. l-chloio-Z-nitro-l-aminobenzene...

2:6 dichloro -4 nitro l amino benzene. 2:4-dinitro-1-eminobenune3-nitro-4-emino-1-methylbenzene l-nitro-Z-amino-l-methoxybenzene.4-nitro-2-amino-1-oxyetbyloxybenzene. 3-nitro-4-amino-1-ethoxybenune.

6-nitro-3-amlno-4-methoxy-1- methyl-benzen e. 3-eminobenzene-lm1lphonioacida amihobenzene-l-eolphonio mid. Hminobenzene-l-sulphonlo acid-4-emlnobenzene-l-sulphonio acid. 4-ehloro-2-aminobenune- 1- mlphonlcacid. o-ohioro-3-aminobenune- 1- mlphonic acid.2:5-dichloro-4eminobenzene-lml honio aicd. 2' hloro -3- aminobenuneleulphonic acid. 3-nitro-4-eminobennene l sulphonic acid.4-nitro-2-eminobenune 1 eulphonio b-nitro-z-eminobenzene 1 sulphonicacid.

Powerful orange-yellow.

Brownish-orenge--- Orange-yellow Powerful yellow Pele Bordeaux redPowerful brownish-red Brown-orange Pale yellow-brown 3 {:liidxyethyhminobenzene 1 sulphonic Red-violet--- s dloxyetbylemino-benzene-l-sulphonicacid..- Reddish-yellow 3-dioxyethyleminobenzene-l-sulphonic acid.Brownish-orange 3-dioxyethylamino-benzene-l-sulphonic acid.-.Brownish-orenge B-dioxyethylemino-benzene-l-mlphonic acid--.Orange-brown a-dioxyethylemino-benzene-l-sulphonic acid--- Darkred-brown Dloxyethylemino-benzene Pure yellow admin?2%,?mei-miltttreu::: nfiddfih ififi lx:::::::::::

Di-(p: -dioxy)-propyleminobenzene Powerful reddish-yellow 3-di gc-yggioxy) ethylaminobenzene -1 sul- Pale brownish-orange -(p= y-dioxy)etbylamfn'obenzene 1 sul- Brownian-orange D 25 m yypropyleminobenzenehBrownorange a-N-ethyloxy-ethylamino-benzene-l-eulphonio Brownishyeilowoi'fieeyfmm Dull yellow a-oxyethylamino-bmethylbenzeneBrown-yellow a-dioxyethylemino-l-methyl-benzene Orange-brownf-ehloro-Z-dloxy-ethylemino-l-methoxybenzene Brown-yellow3-dloryethylamino-l-oxy-benzene; Powerful brownish-yellow...

3-m-hyloxyethylamlnobenzene -l sulphonio Deep Bordeaux red Oxyethylamin-Violet-bro" Powerful orange-yellow Powerful brownish orange.Orange-yellow.

ow. Orange-brown.

pure yel- Brownish-orange.

Powerful brownorange.

Powerful brownish yellow.

Brownish yellow.

Powerful brownorenge.

Deep orange-brown.

Brown-yellow.

Powerful brownish yellow.

Deepredviolet.

Violet-brown.

aeeaere 3 Dyestufi Dyeing on leather Diem-component Azo-component 0n thesurface in the interior 2.4 5 nitro 2- aminobenzeuo 1Dioxyethjriaminohenaene- Pure Bordeaux red i-Poweriui Bordeaux sulphonicacid. red. 35 5 nitrg 2 ernnobenzene 1 fl-oxyethyiamino-l-methylbenzeneBordeaux red Bordeaux red.

su p omc ac: E5 5 nitro 2 aminobenzene 13-11ioxyethyiamino-l-methyibenzene Bordeaux red Deep dark-violet.

suiphonic acid. 1, Q 37 5-111i1tro -2-an1inobenzene-1 -suia-di-(fi:-dioxy)-px-opylamino-1-methyihen- Pele Bordeaux red r- Bordeaux red.

p onic aci cane. 38 5-nli tro;2-a 1(1 1inobenzene-1-sn1- 3chiorodioxyethyi-aminobenzene Deep Bordeaux red" Dark red-violet.

p omc 801 39 fi-ngtro-Z-arafinobenzenml-sui- 3-ch1orodi-(fl:'y-dioxy)-propyi-aminobenzene Bordeaux red Deep Bordeaux red.

p 01110 e01 405-nlgtroflerginobenzene-i-snili-oxyethylemino-e-methoxy-1-methyibenzoneViolet-brown Deep violet-brown. W1 5 p 01.110 801 v .i 115-nitro-2-aminobenzene- 1- sul- 3-dioxyethyiamino-4-methoxy-1-methy1ben-Grey-brown Grey phonic acid. zone. 42 5-nitro-2-aminobenzene-i-sul-3-di-(fi: v-dioxy) -propylamino-4 -methoxy-1- Red-brown. Rod-brown.

phonic acid. methylbenzene. 43 5 nitro 2 aminobenzene i sul-2-dioxyethyiamino-iz-dimethylbenzene Yellow-brown. Brown-violet.

phonic acid.

What 1 claim is:-

1. A process for dyeing leather, wherein the leather is dyed with anamino-azoioenzene sulphonic acid dyestufi of the following generalformula:

wherein X1 represents H or SOaH; X2 represents H, N02, Cl, CH3 or OR (Rbeing methyl, ethyl or hydroxyethyl) X3 represents H, N02, C1 or CH3; X4represents H or N02, with the restriction that at least one of said X1,X2, Ya and m must be other than hydrogen; Y1 represents H or SOsH; Y2represents H, CH3, C1 or OH; Y3 represents H, CH3 or OCHa; R1 representsH, ethyl, hydroxyethyl or dihydrozypropyi; and R2 representshydroxyethyl or o'lihydroxypropyl.

2. A process for dyeing leather, wherein the leather is dyed with a.dyestuff from diazotized 4-nitro-2-aminobenzene-1-su1ph0nic acid and 3-hydroxyethyiamino-l-methylbenzene, having the formula:

3. A process for dyeing leather, wherein the ieather is dyed with adyestufi from diazotized 3-aminohenzene-i=suiphonic acid and dihydroxy=ethyiaminohenzene, having the formula:

25 canon NN P \\-N/ CalhOH e0 4. A process for dyeing leather, whereinthe leather is dyed with a dyestuff from diazotized 3-aminobenzene-i-suiphonic acid and di- (pw-dihydroxy)-propy1aminobenzene, having the formula:

5 /on,.onon.cmon u GH:.CHOH.CH2OH 0:11

mm- SENN.

